Workpiece materials which have a hexagonal lattice structure such as inconel, titanium, cobalt, and the like toughen and become more difficult to machine when a cryogenic fluid is applied to the surface of the material. For this reason, it is advantageous to cool a cutting tool internally when using a cryogenic coolant rather than spray the cryogen coolant on the workpiece when machining such materials.
The increase in cooling on the cutting edge will allow an increase in cutting speed. For example, a 100% increase in cutting speed in titanium material will result in a 30% increase in heat. This means that a 30% reduction in heat at the cutting edge will allow the cutting edge to operate at twice the cutting speed without exceeding the original operating temperature. A tool that is operated at a cutting speed that is twice the original cutting speed can cut the same amount of material in half the time.